Process of increasing the yield of light hydrocarbons from oil shales



Nov. 24, 1931. 1,833,155 PROCESS OF INCREASING THE-YIEILD OF LIGHTHYDROCARBONS FROM OIL SHALES sf DANNER ET AL Filed Sept. 28, 1925 nm (06L OHIIN Iain/40E Patented Nov. 24, 1931 UNITED STATES PATENT OFFICEPHILIP s. BANNER, or rorNr RICHMOND, AND ERNEST E. LYDER, or BERKELEY;CALI- FORNIA, ASSIGNORfi, BY MESNE ASSIGNMENTS, TO STANDABD OIL .COMPANYOF.

' CALIFORNIA, OF SAN FRANCISCO, CALIFORNIA, A CORPORATION OF DELAWARErzaoenss or INCREASING rHE-YrnLn or LIGHT HYDROCARBONS FROM. on. SHALESApplication filed September This invention relates to processes oftreating oil shales to obtain various products therefrom, and an objectof the invntion is to secure a more complete recovery of the carbon,present in the shale, as light hydrocarbons of a superior quality.

0 nite temperature.

- slowly inward from the surface of the shale particles. At temperaturesslightly above this temperature of transformation the soluble, bitumenbegins to distil from the mineral matter, which constitutes the body ofthe shale, and at the same time to crack to lighter hydrocarbonproducts.

'v A large amount-of carbon is deposited in the ash during the crackingof the soluble bitumen and the crude shale hydrocarbons have a lowdegree of saturation. Hydrogen containing gas, if introduced atatmospheric pressure, diffuses but slowly through the layer of ash lefton the surface of'the par ticles of shale as the cracked products arevaporized and carried away, and consequentlyit is always relatively farremoved from the z'oneof reaction as said zone proceeds toward thecenter of the shale particles. Accordingly, it will be seen that therecan be little, if any, benefit derived from the presence, of thehydrogen-containing gas introduced at atmospheric pressure to the retortexcepting, possibly, for a slight buffer action in protecting thehydrocarbonmolecules from the superheated walls of the retort. r

We have discovered that, by circulating hydrogen-containing gas underhigh pressure and temperature through the retort,

such hydrogen gas serves to convey the requisite amount of heat to thezone where the reactions should be completed in order to utilize thecarbon'content of the shale,

and the hydrogen-containing gas also serves to remove the prodgcts ofthe reaction.

When hydrogen-containing gas,'1inder relatively highpre'ssure andtemperature is in- 28, 1925. Serial No. 59,106.

troduced to the retort, the highly compressed gas diffuses readilythrough the porous ash to'the region of reaction and because ofsuch'gases possessinga relatively'great capacity for'heat, the temperature ofthe shale mass. is raised without difficulty to a degree sutficientlyhigh for rearrangement of the molecules and also the temperature may beraised sufliciently for. cracking with sufli cient uniformity andrapidity so that the several reactions may proceed as a substantiallysingle rearrangement instead of in gen is not circulated under highpressure. The presence of highly reactive hydrogen because of, theporosity of the shale at the immediate point at which these extensivemolecular rearrangements are taking place permits of the nearly completesaturation of the chemicalatfinity of the carbon atoms, and thusprevents the separation of free carbon atoms and insures a high degreeof saturation of the products" formed. This may result in increasing theyield of light hydrocarbon materials by as much as from fifty to onehundred per cent. I

The hydrogen-containing gas may be'employed under pressures of about 50up to 250 atmospheres and undertemperatures of about 400 C. to 500 C.Inthe-present proc-' 'ess the shale may be employed as mined andcjrus'hedto from one to two inch mesh. The oil shale subjected to theoperations of this process may have associated with it, coal or amaterial occupying the region between shales and lignit'es, but suchcoal'or other associated material does not have the porosity that is animportant factor in, this.

process. and, therefore, theshale shouldbe in predominating volume;

It is well known th t many reactions, in; vol-ring one ormore gases, arevery materia lly hastened by the presence of certain: highly poronismaterials such as the many forms of actiire charcoal and silica-gel. Anexactly analogo s action is obtained in this separate steps as resultswhen the hydroprocess by the presence of thehighly porous V shale ashwhich markedly increases the activity of the hydrogen. The beneficialeffect,

obviously, will vary somewhat with theloo respectively, and removablecovers 12 are pro I chemical nature of theash from different shales butto a far greater degree the effect will vary with the physical structureof thei ash and, accordingly, the pressure of the hydrogen used in theprocess for securing a given amount of hydrogenation may vary betweenwide limits. The partial pressures of hydrogen employed may vary fromabout 800 lbs., per square-inch-to well above 2000 lbs, per square inch.Pressures of about 1000 lbs., are preferred.

The'yield of ammonia is highly sensitive to the amount of water vaporpresent in the gases of the retort. For this reason it will be usuallydesirable to circulate a small per cent of steam along with the hydrogenin the retort. The addition of steam may not be necessary during theearly stages of the retorting as sufficient moisture will usually befound in the shale to generate the necessary steam, but after thismoisture has disappeared the supply will need to be augmented fromwithou v I As the reaction progresses hydrogen is used up and lighthydrocarbons are produced, thus making it necessary to eventually removethe fixed hydrocarbon vapors and replenish the supply of hydrogen. Theseends may be accomplished by the catalytic decomposition of the lighthydrocarbons, such, for example, as propane, butane, methane and thelike, without their removal from the circulating gases, thus materiallyreducing the amount of hydrogen that must be supplied. It isto beunderstood that pure hydrogen gas is not required, and any gascontaining hydrogen in sulficient quantities to be effectively used,such as gas from the-catalytic decomposition of light hydrocarbonmentioned above, may be employed. Pure hydrogen 'gas is, of course,preferredbu-t its use may not be economically possible under someconditions.

The process may be performed in any suitable apparatus and one suchapparatus is v illustrated in the accompanying drawing which is a more'or less diagrammatic view thereof. r y

The apparatus illustrated is constructed as follows:

There is provided. a heater o j furnace 1' and inside thereof is ahydrogen-containing gas heating coil 2. The furnace may be heated by anysuitable means, as by gas flowing frdm a gas holder 3 through a pipe 4to a burner 5' positioned in the combustion chamber of the furnace.

The lower end of the coil 2 is connected by a branched pipe 6,providedwith valves 7,

71, with the 'l puwer portions of retorts 8,9.

- iiicient for carrying out the process, but whena. plurality isemployed the process is semi-continuous. The retorts 8,9 are fed withshale from hoppers-10, 11,

vided to close the upper ends of the retorts during the retoftingoperation. Also the lower'ends of the ret-orts 8, 9 are likewlse closedby removable covers 13. Below the 4 retorts 8,9 are ash conveyin means14 which,

in this instalfce, are in the orm of cars run-- desired place ofdischarge. Leading into the trap 24 is a pipe 27 having a valve 28 andleading from the lower portion of a trap 29. Leading from the upperportion of the trap 29 is a by-pass pipe. 30 having a valve 31 andconnected with the pipe 20 between the pump 21 and purifier 19.

Leading into the upper portion of the trap I 29 is a condensate pipe 32connecting with a water cooled condenser 33, and leading to saidcondenser is a vapor pipe 34 that is connected with the upper end of atrap 35. Leading from the lower portionof the trap 35 is a condensatepipe 36 which is branched'and which connects with the upper portionsofthe retorts 8, 9. The pipe 36 is provided with a'valve 37 and withvalves 38, 39 on its branches.

Leading into the trap 35' is a condensate pipe 40 that connects with anair cooled condenser 41 which in turn is connected by a branched vaporpipe 42 with the'u'pper portions of the retorts 8, 9, the branches ofsaid pipe being rovided with valves 43, 44. The

branches 0 the pipe 42 are-connected by a branched pipe 45 with a pump46,'and the branches of the pipe 45 are rovided with valves 47, 48,respectively. onnecting the pipe 45 with agasholder 49. is a pipe50'proipe 42. The branches, of r i I vided with valves 53, 54, 55,respectively. 1 r

The branch of the pipe 52 on which is positioned the valve 55 connectswith the lower end of the gas holder 3. Connected with the branches ofthe pipe 6 arepipe 56, 57 provided, respectively, with valves 58, 59. I

The process is performed in the apparatus above described as follows; IThe shale is charged from one of the'hoppers 10, 11 into the associatedretort. For example, it may be assumed at the beginning that the shaleis discharged from the hopper 10 into the retort 8.- Before charging,the cover 12 is removed and after the charging is completed thecover 12will be secured in place. Hydrogen-containing gas from a suitablesource, for example from the gas holder 49, will then be pumped into theretort 8 by operation of the pump 46, all valves being closed excepting51, 53, 43, 31, 71 and 28. When the system, including the retort I 8,the condensers 33, 41,.the traps 24, 29, 35, the purifier ,19, the pump17 and the heating coil 2 ispumped to the proper pressure by operationofthe pump 46, the valves 51 and 53 will be closed and the pump 46stopped. The pressure is. comparatively.

high, for example, around 250 atmospheres.

Then the circulating pump 17 is started into operation and the furnaceis heated sov as to heat the coil 2. The hydrogen contain ing gases willbe heated in the coil 2 and will pass therefrom into the retort 8 andwthrough the mass of shale in said retort. thence-into the condensers41-, 33. 'Because of the porosity of the shale, the hydrogen gasthoroughly and quickly penetrates the shale, and this results in thehydrogen being present at the immediate point at which the molecularrearrangements are taking place, permitting of the nearly completesaturation of the carbon atoms, thus preventing the production of freecarbon atoms and insuring a high degree of saturation of the desiredproducts. ,The increase in the yield of light hydrocarbon materialswithin the gasoline range may amount to from 50 to 100%. The

. reaction of the hydrogen gas with the hydrocarbon is materiallyhastened by reason of the reaction occurring in the presence of thehighly porous shale, similar to the increased chemical reaction thatoccurs in the presence of active charcoal and silica-gel.

As the circulation of the hydrogen-containing gas continues, the,pyrobitumen in the shale is decomposed and the bitumen hydrogenated,cracked and distilled in the retort. The heavy vapor products, carriedout of the retort with the gases through the pipe 42, are condensed inthe condenser 41. i The heavy liquid products are caught in the trap'35and the gases and lighter vapors pass on to the condenser 33. Theseheavy liquid productsmay be returned, if desired. to the 7 retort 8 forfurther cracking by opening the valves 37, 38. i 7

The lighter vapors are removed in the condenser 33 and caught in thetrap 29 and theymay be drained, from time to time, into the trap 24 inwhich the pressure is relieved and from which the liquid products aredrawn oi f by opening the valve .26. v

The gases which remain when the pressure is relieved in the trap 24, arepumped back into the system by operating the pump 21 I which forces thegases through the purifier 19. The purifier 19 may be charged with suchreagents as will remove detrimental impurities. From the purifier thegases are again circulated by operation of the pump 17, and

of hydrogen-containing gas, the valves 51 and 53 will be opened and thepump 46 operated.

The circulation of the hot hydrogen-cbhtaining gases is maintained untilsuch time as it is found that substantially all of the pyrobitumen inthe shale has been converted into the desired products.

In order to remove thegases from the re-- tort 8 and carry them to theretort 9, the pump 46' is operated and the valves 47 and 54 will beopened and the valves 43, 53, 71 and 38 will be closed. For still morecompletely 'r'emoving the gases from the retort 8 it may be necessary toopen the valve 58 and 1111801, steam into said retort. When all thegases are exhausted from the retort 8, the valves 47, 54

Will be closed, valves 44 and 7 opened, and the treating of the shalein'the retort 9 will be effected the same aspreviously described for 4the shale in the retort 8. While the shale in the retort 9 is beingtreated, the covers 12, 13 of the retort 8 will be removed and theresidue dumped from the retort 8 into theassociated car 14. V

The form of construction of the furnace 1 will depend on the dispositionit is desired to make of the fixed gases produced during the reaction inthe retorts, or, in other words,

whether or not it is desired to burn the excess fixed gases in thefurnace. Such gases will accumulate and, if not removed produceundesirable dilution of the hydrogen. 'The introduction of the necessarycatalyst and the operation of an apparatus for cracking these gases toproduce hydrogen and carbon black or to effect polymerization to liquidhydrocarbons need not affect the operation of the process abovedescribed.

Under-certain conditions it may be found necessary to remove a part orall of the fixed ,gases from the system ratherthan to pump them toanother retort. This can be done by opening the valve 55 and operatingthe pump 46 to force the gases to the gas holder 3.

These gases can then be conveyed to the furj nace through the pipe 4 andburned, if that be desired. 1

It will be readily understood that in the process the materials to betreated are placed in a circuit of hydrogen-containing gas underpressure, and that the gas is heated while circulating.

We claim: 1. The process of increasing the'yield of light hydrocarbonsfrom oil shales which consists in charging the oil shale into anenclosed space, compressing a hydrogen-containing gas to a pressure ofabout 250 atmospheres, heating thecompressed gas to a temperature ofabout 500 degrees C., circulating the hot compressedhydrogen-containinggas through the enplosed-space to decompose andhydrogenate and crack and distil the pyrobi tumen in the shale and tocarry ofi the reshltingheavy and light vapor products and the time oftheir formation from kerogen in J such pyrobituminous oil shale,permitting the current of gas to carry the resulting heavy and lighthydrocarbon vapors out of said reaction zone, condensing and separatingheavy hydrocarbons from said current of gas, and

0 condensing and separating the light hydro: carbon vapors from the unndensible gases.

3. The process of increas ngthe yield of light hydrocarbons frompyrobituminous oil shales, which comprises forming a bed of ap-yrobituminous oil shale in a pressure rerobitur'ninous oil' shale,removing the resulting mixture of light and heavy hydrocarbon vapors andhydrogen and fixed gases from said pressure reaction zone, condensingand separating heavy hydrocarbon vapors from said mixture of vapors andgases, condensing and withdrawing light hydrdarbons, from theuncondensed hydrogen-containing gas,

and reusing uncondensed hydrogen-contain- 7 in gases in cyclic operationof the process. igned at Richmond, California this 12th day of September1925.

PHILIP S. DANNER. ERNEST E. LYDER.

action. zone, compressing hydrogen gas to a pressureabove 800 lbs., persquare lnch, heat: ing the compressed gas to above 400 (1., passing thehot compressed gas through the reaction zone to remove moisture fromsaid pyrohot compressed gas therethrough so as to hydrogenatehydrocarbons at the time of their formation from said pyrobituminous oilshale, removing the resulting mixture of light j and heavy hydrocarbonvapors and hydrogen and fixed gases from said pressure zone,

condensing and separating heavy hydrocarbon'vapors from said mixture ofvapors and gases, and finally condensing and separating lighthydrocarbons from the uncondensed hydrogen-containing gas.

4. The process of increasing the yield of light hydrocarbons frompyrobituminous oil shales which comprises forming a bed ofpyrobituminous oil shale in a pressure reaction zone, compressinghydrogen gas to a ressure above 800 pounds per square inch, eatin g thecompressed gas to above 400 0., and passing the hot compressed hydrogengas through the reaction zone to remove moisf turefrom saidpyrobituminous oil shale, 'con tinuing to .pass the hot compressed gastherethrough so as to hydrogenate hydrocarbons -at the time of theirformation from said pybituminous oil shale, continuing to pass the

